We have never had to reserve a bed on the beach and honestly don't get down there until 9:00 or 10:00, and there is always one available. Hope I didn't just jinx us for our upcoming trip.
Also there is no charge but I do tip Renee and he typically sees us each morning and goes ahead and gets us a bed without asking.
The jacuzzi beds are not available to reserve and I agree with texascouple on the courtesy. For us we do not use the beds by the jacuzzi unless we are playing as if we are not playing we are usually in the jacuzzi or standing at the bar.
Not sure about the beds by the pool but they are typically always full so that definitely would be one I would get up early for if you are wanting a bed by the pool.
We typically get the beach bed to relax and enjoy time alone at the beach, and just go into the pool to be social.
Have fun on your first trip!